1. Technical Field
The present invention relates to an apparatus for preparing silicon nanoparticles, which can improve grain size control performance and production efficiency of nanoparticles by preventing agglomeration of the nanoparticles generated by a plasma reactor.
2. Description of the Related Art
Generally, battery capacity of a lithium-ion battery depends on materials used as an anode terminal. For example, a carbon electrode-type lithium-ion battery using a carbon electrode as the anode terminal has a battery capacity of 375 mAh/g, which is a theoretical capacity of carbon (C).
However, the carbon electrode has a fundamental limit in that it cannot be applied to a high-capacity lithium-ion battery due to a theoretical capacity of carbon (C) of 375 mAh/g, despite merits of carbon (C) exhibiting excellent charge and discharge efficiency.
Thus, in order to realize the high-capacity lithium-ion battery, it is necessary to use a material, which can be used as an anode terminal and has higher theoretical capacity than that of carbon (C).
One example of such a material includes silicon (Si). Silicon (Si) has a theoretical capacity of 4200 mAh/g, which is higher than that of carbon (C), and is selected as an optimal material capable of realizing a high-capacity lithium-ion battery.
However, although silicon (Si) has a theoretical capacity of 4200 mAh/g, a silicon electrode-type lithium-ion battery using silicon (Si) as the anode terminal undergoes extremely high volume expansion up to about 400% due to formation of Li4.4Si by reaction of Li4.4 and Si during charging thereof.
As described above, the volume expansion of about 400% generated in the silicon electrode-type lithium-ion battery can generate cracks of silicon forming a silicon electrode, and can cause short circuit of the silicon electrode in severe cases.
However, silicon (Si) also reduces stress caused by volume expansion when a particle size thereof changes from micrometer scale (μm) to nanometer scale (nm), and the silicon electrode is formed of nanometer scale (nm) silicon particles using such properties, thereby easily realizing a high-capacity lithium-ion battery.
Thus, various methods and apparatuses for preparing nanometer scale (nm) silicon particles from silicon (Si) have been developed and applied in the art.
Examples of such methods include methods of preparing silicon nanoparticles via vapor phase or liquid phase reaction. In particular, a method of preparing silicon nanoparticles using plasma has significantly improved production efficiency (=an amount of prepared nanoparticles/an amount of input raw materials), which is required to reduce manufacturing costs, and thus is broadly applied in the art.